The Uchiha are not direct descendants of the Elder Brother. It is actually the Uzumaki who are the direct descendants, just look at their clan symbol ffs:
You must be registered for see images
The Elder Brother is not related to Sage of The Six Paths.
You must be registered for see images
LOL Sage ain't got enough swag!!!!!!
The Elder Brother is a descendant of Simon from Gurren Lagann, you can clearly see they have similar eyes:
You must be registered for see images
It is just that the spiral genes have filtered down through the ages.
So it is confirmed, Naruto Uzumaki has spiral powers that is why he can go from complete fodder to being one of the strongest in the series It doesn't matter how strong Sage Obito currently is, Naruto becomes stronger with every passing second.
This could also be the reason why the Uzumaki clan was wiped out, due to the fear that they may become too powerful.
Why do Uzumaki have red hair? Duurrrr Simon obviously had a kid with Yoko.